import argparse
import sys
import os

def parse_args():
    parser = argparse.ArgumentParser("")
    parser.add_argument("--input", type=str,required=True)
    parser.add_argument("--output", type=str,required=True)
    return parser.parse_args()

def main():
    args=parse_args()
    key_set=set()
    wf= open(args.output, 'w')
    with open(args.input, 'r') as f:
        for line in f:
            words=line.strip().split('\t') 
            key='||'.join(words[:2])
            key_set.add(key)
    for key in key_set:
        wf.write(key+'\n')
                


if __name__ == '__main__':
    sys.exit(main())